Feb. 29 (Bloomberg) -- China National Offshore Oil Corp.'s $16 billion plan to develop an Iranian gas field is a ``commercial act,'' a Chinese official said, as pressure grows from the U.S. for fresh action over Iran's nuclear program.

``China is paying close attention to the nuclear issue in Iran,'' foreign ministry spokesman Liu Jianchao said at a regular briefing in Beijing yesterday. China National's plan ``is a specific commercial act,'' he said.

Iran has rejected two United Nations Security Council demands that it stop enriching uranium, a process the U.S. and its European allies say they suspect is intended to produce nuclear weapons. The U.S., Britain and France will seek a Security Council vote tomorrow on a draft resolution that would impose a third round of sanctions.

Iran postponed the Feb. 27 signing of a contract with China National Offshore because a religious holiday in the Middle Eastern nation made the timing unsuitable.

The agreement between the parent of Cnooc Ltd. and Iran's Pars Oil and Gas Co. may be signed next week, Berouz Majedi, in charge of press affairs at the Iranian company, said Feb. 27.

Iranian businesses and government offices were shut yesterday for Arbaeen, which marks the end of a 40-day mourning period following the martyrdom of Imam Ali, the first Shiite Imam and the grandson of Islam's Prophet Mohammad. There is no newspaper circulation today either, for the Iranian weekend.

An initial agreement between Iran and China National Offshore, the nation's third-largest oil producer, to develop the North Pars project has been signed, Iranian Oil Ministry Kazem Vaziri-Hamaneh said May 2.

The field in the Persian Gulf holds an estimated 80 trillion cubic feet of gas. It is 85 kilometers (53 miles) north of the South Pars field, the world's biggest gas deposit, which Iran shares with Qatar.

A 1996 law in the U.S. calls for penalties on foreign companies that do business in Iran.

To contact the reporter on this story: Ying Lou in Hong Kong at ylou1@bloomberg.net.

Last Updated: February 28, 2008 23:25 EST